1. What is the significance of understanding the characteristics of the earth

The Earth is a spherical object which rotate on it's axis. Earth is one of the planets which rotate round the sun.

Earth movement round the sun is called earth revolution. It takes the earth 364¼ days to complete one revolution.Earth rotation is the movement of the earth round it's own axis.

Earth is the only planet that supports life of living organism. The earth comprises of

Atmosphere: The gaseous part of the earthHydrosphere: The water part of the earth which makes about 70% of the earthBiosphere: The part of the that supports life. it comprises of plants and animals.Lithosphere: This is the soil part of the earth. Natural resources such as crude oil, gold are mined from this part.

The significance of understanding the characteristics of the earth is to "know how to live healthy and be aware of our environment".

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I’m pretty sure it’s 4, you can check on the calculator